This paper summarizes eight-year trial of calcium-magnesium corrective supply to dark tobacco cultivated in bi-annual rotation with winter wheat. The use of magnesium limestone progressively increased the pH of the soil. An average gain of 1 unit of pH for a total value of 8-10 t in splits supplies, was noted. At subsoil level (_ 30 to _ 60 cm) an increase of about 20% less than that of the top soil was observed. The yield and combustibility of tobacco tended to increase after the first treatment with the corrective supply and to stabilize during the later years of the trial. The magnesium content of tobacco increased regularly up to a value of 80 to 90 meq. per 100 g dry matter. This brought about a limited decrease in potassium content of about 10 to 15% for the highest rates of treatment. The oligoelement contents of leaves was also affected with the exception of the iron content. Zinc and manganese content decreased strongly. Copper and zinc also decreased but i n a less pronounced manner. Molybdenum increased moderately. The molybdenum, copper and zinc content of certain tobaccos were very weak without any accompanying sign of deficiency.